Sudanese police have beaten and arrested students as protests broke out throughout Khartoum demanding the government resign, inspired by a popular uprising in neighbouring Egypt.

Hundreds of armed riot police on Sunday broke up groups of young Sudanese demonstrating in central Khartoum and surrounded the entrances of four universities in the capital, firing teargas and beating students at three of them.

Police beat students with batons as they chanted anti-government slogans such as "we are ready to die for Sudan" and "revolution, revolution until victory".

There were further protests in North Kordofan capital el-Obeid in Sudan's west, where around 500 protesters engulfed the market before police used tear gas to disperse them, three witnesses said.

"They were shouting against the government and demanding change," said witness Ahmed who declined to give his full name.

Sudan has a close affinity with Egypt - the two countries were united under British colonial rule. The unprecedented scenes there inspired calls for similar action in Sudan, where protests without permission, which is rarely given, are illegal.

Before Tunisia's popular revolt, Sudan was the last Arab country to overthrow a leader with popular protests, ousting Jaafar Nimeiri in 1985.

Galvanised by social networks

Groups have emerged on social networking sites calling themselves "Youth for Change" and "The Spark", since the uprisings in nearby Tunisia and close ally Egypt this month.

"The people of Sudan will not remain silent any more," its Facebook page said. "It is about time we demand our rights and take what's ours in a peaceful demonstration that will not involve any acts of sabotage."

The pro-democracy group Girifna ("We're fed up") said nine members were detained the night before the protest and opposition party officials listed almost 40 names of protesters arrested on Sunday. Five were injured, they added.

Opposition leader Mubarak al-Fadil told Reuters two of his sons were arrested on their way to the central protest.

Editor-in-chief of the al-Wan daily paper Hussein Khogali said his daughter had been detained by security forces since 0500 GMT accused of organising the Facebook-led protest.

Pro-government newspapers carried front page warnings against protests which they said would cause chaos and turmoil.

The Sudan Vision daily's editorial blamed the opposition.

"Our message to those opposition dinosaurs is to unite their ideas and objectives for the benefit of the citizens if they are really looking for the welfare of the Sudanese people," it read.

Prices, frustration rising

Sudan is in deep economic crisis which analysts blame on government overspending and misguided policies.

Early this month the government cut subsidies on petroleum products and key commodity sugar, triggering smaller protests throughout the north.

Sunday's protests coincided with the first official announcement of results for a referendum on the oil-producing south's secession from the north showing an overwhelming vote for independence, which many in the north oppose

Police spokesman Ahmed al-Tuhami told Reuters the police did not have figures for any injured or arrested.

"We did not use more violence than necessary - we did not want anyone to spoil this day with the referendum results."